KR101818150B1 - Electrophoretic display device and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an electrophoretic display device in which an electrophoretic dispersion is embedded in a lower substrate and a method of manufacturing the same, and an object of the present invention is to provide an electrophoretic display device, And a method of manufacturing the same. To this end, the electrophoretic display device according to the present invention includes an upper substrate; A lower substrate including a plurality of pixel electrodes; Barrier ribs formed on the lower substrate and defining a plurality of sub-pixels; A barrier rib formed on the barrier rib; An electrophoretic dispersion contained in each of the plurality of sub-pixels defined by the partition and having a color; And a charged particle filled in the electrophoretic dispersion, wherein the charged particles are white charged particles having a property of reflecting light.

Description

ELECTROPHORETIC DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to an electrophoretic display device, and more particularly, to an electrophoretic display device in which an electrophoretic dispersion is incorporated in a lower substrate and a method of manufacturing the same.

An electrophoretic display device refers to an apparatus that displays an image by using an electrophoresis phenomenon in which colored charged particles move by an electric field applied from the outside. Here, the electrophoresis phenomenon means that the charged particles move in the liquid by the Coulomb force when an electric field is applied to an electrophoretic dispersion (electrophoretic ink) in which the charged particles are dispersed in the liquid.

The electrophoretic display device using the electrophoresis phenomenon has a bi-stable characteristic, so that the original image can be displayed for a long time even when the applied voltage is removed. That is, the electrophoretic display device is a display device suitable for an e-book field in which it is not required to swiftly change the screen because the electrophoretic display device can maintain a certain screen for a long time without continuously applying a voltage.

In addition, the electrophoretic display device is not dependent on a viewing angle, unlike a liquid crystal display device, and has a merit that it can provide a comfortable image to the eye in a degree similar to paper, and thus the demand is increasing.

1 is a view showing the structure of an electrophoretic display device according to the prior art.

1, an electrophoretic display device according to the related art includes a lower substrate 10 and an upper substrate 20 opposed to each other and an electric field interposed between the lower substrate 10 and the upper substrate 20, And a migration film (30).

The electrophoretic film 30 includes first and second adhesive layers 34 and 36 made of a transparent material and a common electrode 38 made of a transparent conductive material and positioned between the first and second adhesive layers 34 and 36, And a plurality of microcapsules 32 having an electrophoretic dispersion. Although not shown in FIG. 1, on the lower substrate 10, a plurality of pixel electrodes facing the common electrode 38 and a plurality of thin film transistors (TFT), which are switching elements for applying a voltage to the plurality of pixel electrodes, .

Here, the electrophoretic dispersion (electrophoretic ink) includes positively charged particles and negatively charged electrified particles, and the charged particles contained in the microcapsules 32 are moved by electrophoresis Thereby realizing an image.

The electrophoretic display device according to the related art is manufactured by manufacturing the upper substrate, the lower substrate and the lamination electrophoresis film 30 and then the electrophoretic film 30 is transferred to the lower substrate 10 and the upper substrate 20 ).

Accordingly, since the upper substrate, the lower substrate, and the electrophoretic film must be separately manufactured, the manufacturing process is complicated and the manufacturing time is long, resulting in an inefficiency. In addition, since an electrophoretic film prepared separately must be applied, the manufacturing cost is increased.

The electrophoretic display device according to the related art has a special adhesive layer in consideration of the contact between the lower substrate 10 and the microcapsules 32 on which a plurality of thin film transistors (TFT) It is necessary to form the upper electrode 34, which complicates the process and requires an expensive material cost.

In the electrophoretic display device according to the related art, it is necessary to form a color filter on the upper substrate 20 for color display. In this case, misalignment between the lower substrate and the upper substrate, Color mixing may occur due to the birefringence problem due to the thickness of the color filter, and it is difficult to express the color primary color.

An object of the present invention is to provide an electrophoretic display device and a method of manufacturing the same, in which electrophoretic dispersion having color and charged particles are embedded in a lower substrate.

According to an aspect of the present invention, there is provided an electrophoretic display device including: an upper substrate; A lower substrate including a plurality of pixel electrodes; Barrier ribs formed on the lower substrate and defining a plurality of sub-pixels; A barrier rib formed on the barrier rib; An electrophoretic dispersion contained in each of the plurality of sub-pixels defined by the partition and having a color; And a charged particle filled in the electrophoretic dispersion, wherein the charged particles are white charged particles having a property of reflecting light.

According to another aspect of the present invention, there is provided an electrophoretic display device including: an upper substrate; A lower substrate including a plurality of pixel electrodes; Barrier ribs formed on the lower substrate and defining a plurality of sub-pixels; A barrier rib formed on the barrier rib; An electrophoretic dispersion contained in each of the plurality of sub-pixels defined by the partition and having a color; And charged particles charged in the electrophoretic dispersion liquid and charged at different polarities.

According to an aspect of the present invention, there is provided a method of manufacturing an electrophoretic display device, including: forming a common electrode on a transparent upper base substrate to form an upper substrate; Forming a lower substrate by forming a thin film transistor and a pixel electrode on a lower base substrate; Forming a barrier rib defining sub-pixels on the lower substrate; Forming a barrier rib electrode on the barrier rib; An electrophoretic dispersion having color in the sub-pixel; and filling the charged particles; And bonding the upper substrate and the lower substrate with the partition wall therebetween.

According to the above-mentioned solution, the present invention provides the following effects.

First, the present invention does not require a separate adhesive layer by internalizing the electrophoretic dispersion having color and the charged particles on the lower substrate, thus simplifying the process and reducing the manufacturing cost.

Second, the present invention can improve the productivity by simplifying the process.

Third, the present invention can prevent mistakes and poor color mixing defects that may occur in using a color filter by internalizing the electrophoretic dispersion having color and the charged particles on the lower substrate.

1 is a view showing a structure of an electrophoretic display device according to the related art.
2 is a view schematically showing an electrophoretic display device according to a first embodiment of the present invention.
3 is an exemplary view illustrating various methods of forming a black layer applied to the electrophoretic display device according to the first embodiment of the present invention.
4 is an exemplary view for explaining a method of displaying various colors using the electrophoretic display device according to the first embodiment of the present invention.
5A to 5G are views showing a manufacturing method of the electrophoretic display device according to the first embodiment of the present invention.
6 is a view schematically showing an electrophoretic display device according to a second embodiment of the present invention.
FIG. 7 is an exemplary view for explaining a method of displaying various colors using the electrophoretic display device according to the second embodiment of the present invention; FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view of an electrophoretic display device according to a first embodiment of the present invention, showing sub-pixels for displaying red, green, and blue.

2, an electrophoretic display device according to a first embodiment of the present invention includes an upper substrate 100 including a common electrode 110, a lower substrate 200 including a plurality of pixel electrodes 210, And a partition wall 314 on which a barrier rib electrode 316 is formed between the upper substrate 100 and the lower substrate 200. The barrier ribs 314 define a plurality of sub- And an electrophoretic layer 300 in which a defined sub-pixel is filled with electrophoretic dispersion liquid 310 and white charged particles 312.

The upper substrate 100 includes an upper base substrate (film) 130 made of transparent glass or plastic, a common electrode 110 formed on the upper base substrate, and a top sealant (120). Here, the upper base substrate 130 and the common electrode 110 of the upper substrate 100 must be transparent to display an image. The common electrode 110 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) . The top sealant 120 is formed so as to smooth the upper substrate 100 and protect the common electrode 110 and smooth adhesion between the electrophoresis layer 300 and the upper substrate 100 .

The lower substrate 200 includes a plurality of gate lines (not shown) and data lines (not shown) formed on the lower base substrate 230 and includes a plurality of sub pixels defined by the barrier ribs 314 (TFT) 220 formed at the intersection of the plurality of gate lines and the data lines to correspond to the plurality of sub-pixels, and a pixel electrode 210 for applying a voltage to the plurality of sub- .

The lower base substrate 230 may be a glass substrate of a transparent material, a plastic substrate or a metal substrate may be used as a base substrate (film) to have flexibility. Here, since the lower base substrate 230 is located on the opposite side of the screen on which the image is displayed, it is not necessarily transparent.

The gate line and the data line may be formed of a single film made of silver (Ag), aluminum (Al), or an alloy thereof having low resistivity, or may be formed of chromium Cr), titanium (Ti), or tantalum (Ta).

A gate insulating film made of a nitride film (SiNx) or the like may be positioned between the gate line and the data line, and a thin film transistor (TFT) 220 is formed at each intersection of the gate line and the data line. Here, the gate electrode of the thin film transistor TFT is connected to the gate line, the source electrode thereof is connected to the data line, and the drain electrode thereof is connected to the pixel electrode 210.

Meanwhile, the electrophoretic display device according to the first embodiment of the present invention can realize black by the black layer 240 capable of absorbing light, and the black layer 240 is formed on the lower substrate 200 ). In FIG. 2, an example in which a protective layer for protecting the TFT 220 is used as the black layer 240 is shown in particular. The black layer 240 will be described in detail with reference to Fig.

The electrophoretic layer 300 includes an electrophoresis layer 314 formed in each of a plurality of subpixels defined by the barrier ribs 314 defining the plurality of subpixels, the barrier ribs 316 formed on the barrier ribs, Dispersion 310 and white charged particles 312.

The barrier ribs 314 are formed on the upper substrate 100 or the lower substrate 200 to define a plurality of sub-pixels. That is, the barrier ribs are formed on the lower substrate 200 so as to surround the pixel electrode 210 to define a plurality of sub-pixels in which an image is displayed. The electrophoretic dispersion 310 containing a plurality of white electrified particles 312 charged with a positive (+) or negative (-) polarity is internalized in the sub pixel defined by the partition 314.

The electrophoretic dispersion 310 may be formed by a variety of methods such as a die coating method, a casting method, a bar coating method, a slit coating method, a dispensing method, a squeezing method, Pixel, a sub-pixel on a lower substrate 200, a screen printing method, an inkjet printing method, and a photolithography method.

The electrophoretic dispersion color liquid phase may be embodied as red (R) electrophoretic dispersion 310a, green (G) electrophoretic dispersion 310b, blue (B) electrophoretic dispersion 310c, ), Cyan, magenta electrophoretic dispersion, and the like. That is, the sub-pixels according to the present invention can implement various colors according to the color of the electrophoretic dispersion 310 contained therein.

The barrier ribs 314 are formed on the lower substrate 200 such that they are perpendicular to the upper substrate 100 on the lower substrate 200 and have physical properties similar to those of the electrophoretic dispersion 310 And may be formed of an organic material including an insulating polymer. The barrier ribs 314 may be formed through a photolithography process or a mold printing process and are formed to have a height of 1 to 100 탆.

The electrophoretic dispersion 310 includes a plurality of white charged particles 312 charged with a positive (+) or negative (-) polarity.

On the other hand, the barrier ribs 316 are formed on the barrier ribs in contact with the electrophoretic dispersion to form a transverse electric field in the electrophoretic dispersion.

The barrier rib electrode 316 may be formed only on the barrier rib surface in a flat plate shape as shown in FIG. 2A (hereinafter, simply referred to as a 'barrier rib surface electrode'), (Hereinafter, such a barrier rib is simply referred to as a 'bottom barrier rib'), the barrier rib surface electrode 316a and the barrier rib bottom barrier rib 316b may be formed to be parallel to the pixel electrode at the lower end of the barrier rib surface And the second electrode 316b. Meanwhile, the shape of the barrier rib electrode may be applied to the electrophoretic display device according to the second embodiment of the present invention, which will be described with reference to FIGS. 6 and 7. FIG.

The first embodiment of the present invention as described above is characterized by a structure in which an electrophoretic dispersion liquid having a color is directly formed on a lower substrate, and includes a charged particle 312 having one charge characteristic Color, black, and white are implemented through the movement of charged particles in an electrophoretic dispersion composed of fluids of different colors. Particularly, a color filter (C / F) ) Can be implemented without color.

Further, in the first embodiment of the present invention, the barrier ribs may be formed on the upper plate, but are formed on the lower plate rather than on the upper plate.

In addition, the first embodiment of the present invention is characterized in that white charged particles are used as the charged particles 312 having charging characteristics, and as such white charged particles, Good particles can be used.

In the electrophoretic display device according to the first embodiment of the present invention configured as described above, the electrophoretic dispersion liquid (hereinafter, referred to as " White or black of the electrophoretic dispersion as the white charged particles 312 in the electrophoretic dispersion liquid 310 are moved to the pixel electrode 210 or the bank electrode 316 in the electrophoretic dispersion liquid. And the implemented image is displayed through the upper substrate 100. [ This detailed operation method will be described below in detail with reference to FIG. 4. Hereinafter, referring to FIG. 3, a method of forming a black layer required for the present invention to realize Black will be described.

3 is a view illustrating various methods of forming a black layer applied to the electrophoretic display device according to the first embodiment of the present invention.

As described above, according to the electrophoretic display device of the first embodiment of the present invention, color, white, and blue are formed according to the position of white charged particles due to the voltage applied to the barrier rib electrode 316 or the plurality of pixel electrodes 210, In particular, black is realized in such a manner that light incident through the upper substrate is absorbed by the lower substrate in a state in which charged particles are accumulated in the barrier rib electrode 316. For this purpose, A black layer 240 capable of absorbing light must be formed.

That is, in the first embodiment of the present invention, a black layer is formed before the TFT process or after the TFT process, or a conventional passivation layer is formed as a black layer .

Here, as a material forming the black layer, a material containing Black Dye or Pigment may be applied to an insulating organic material such as carbon black PR or photo acryl. That is, an insulating organic material having a black color may be used for the black layer. Examples of the organic material include photo resist materials including BM PR, Black Dye / Pigment, and other black organic insulating materials.

Meanwhile, the black layer may be formed by a method of coating the entire surface of the lower substrate, and the following three methods can largely be applied as a forming method.

A first method is a method of forming a black layer before a process of forming a TFT. As shown in FIG. 3A, a black organic insulating material is coated on the entire surface of a lower base substrate 230 in an initial state Thereby forming a black layer 240a. This method has an advantage that an inorganic film can be formed on the black organic film (black layer) formed for the purpose of process stability and prevention of outgas.

The second method is a method of forming a black layer during the process of forming a TFT. As shown in FIG. 3 (b), when a gate insulating film or a passivation layer is formed, Thereby forming a black layer 240b. In order to improve the black characteristic, it is preferable to form the protective layer as a black layer as in the second method.

A third method is a method of forming a black layer after completion of the process of forming a TFT. As shown in FIG. 3C, a black layer 240c is thinly coated on the entire surface of the pixel electrode 210, Thereby preventing a voltage drop (Drop) from occurring when an electric field is formed. At this time, the thickness of the black layer is preferably 30 占 퐉 or less, and the optimum thickness is preferably 5 占 퐉 or less.

On the other hand, among the above-mentioned three methods, the second method of forming the protective layer as the black layer during the process of forming the TFT is most preferable from the viewpoint of process simplification.

FIG. 4 is a diagram for explaining a method of displaying various colors using the electrophoretic display device according to the first embodiment of the present invention. Meanwhile, the white charged particles 312 included in the electrophoretic dispersion 310 applied to the electrophoretic display device according to the first embodiment of the present invention may be charged with a positive (+) or negative (-) polarity Hereinafter, for convenience of explanation, various color display methods of the first embodiment of the present invention will be described by way of example in which the white charged particles 312 are charged with a negative (-) polarity.

First, when the electrophoretic display device according to the first embodiment of the present invention implements color, the pixel electrode 210 is provided with the opposite polarity to the white charged particles 312 as shown in FIG. 4 (a) (+) Polarity having a positive polarity is applied. At this time, the white charged particles 312 charged in the negative polarity move in the direction of the pixel electrode and are floated on the upper surface of the pixel electrode. Therefore, the light that is introduced into the sub-pixel through the upper substrate is reflected toward the upper substrate again by the white charged particles that are concentrated on the upper surface of the pixel electrode. At this time, (Red) corresponding to the color liquid phase of the electrophoretic dispersion liquid is realized because it is transmitted through the dispersion liquid 310a and is emitted to the outside.

Next, when the electrophoretic display device according to the first embodiment of the present invention implements white, as shown in FIG. 4 (b), the pixel electrode 210 is provided with a negative -) polarity is applied. At this time, the white charged particles charged with a negative polarity move in a direction opposite to the pixel electrode, that is, in the direction of the common electrode formed on the upper substrate, and are floated on the surface of the upper substrate. Therefore, the light that is to be introduced into the sub-pixel through the upper substrate is again reflected to the outside by the white charged particles 312 disposed at the boundary between the sub-pixel and the upper substrate, thereby realizing white.

Lastly, FIGS. 4 (c) and 4 (d) illustrate a method of implementing black using the electrophoretic display device according to the first embodiment of the present invention.

That is, when the electrophoretic display device according to the first embodiment of the present invention implements black, as a first method, as shown in FIG. 4C, the side wall electrodes (+) Polarity voltage having a polarity opposite to that of the charged particles is applied to the sidewall surface electrode (sidewall surface electrode) 316a as shown in FIG. 4 (d) (+) Polarity voltage having a polarity opposite to that of the charged particles can be applied to the sidewall electrode (sidewall bottom electrode) 316b which is formed so as to be formed. At this time, the white charged particles charged with the negative polarity move in the direction of the side wall electrodes 316a or 316b formed on the right and left of the sub pixel, and are floated on the side wall electrodes. Accordingly, the light introduced into the sub-pixel through the upper substrate can be introduced toward the lower substrate without being disturbed by the white charged particles, and the light introduced toward the lower substrate is transferred to the black layer 240 to absorb black. On the other hand, in the case of the second method using the lower-side electrode 316b of the side wall, some of the light introduced into the sub-pixel is not absorbed by the black layer, but by the white charged particles 312, The black efficiency may be degraded because it can be reflected, but the sidewall bottom electrode also needs to be considered in light of circuit implementation problems.

Hereinafter, a method of manufacturing the electrophoretic display device according to the first embodiment of the present invention will be described with reference to FIG.

5A to 5G are views showing a method of manufacturing the electrophoretic display device according to the first embodiment of the present invention.

5A, an ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) film is formed on an upper base substrate (film) 130 made of transparent glass or a flexible transparent plastic material, The common electrode 110 is formed of a conductive transparent material.

Then, as shown in FIG. 5B, a top sealant 120 or the like is formed on the common electrode 110 for bonding with the lower substrate or the electrophoretic layer, thereby completing the upper substrate. Here, the upper substrate 100 uses a glass or plastic substrate as the upper base substrate 130, and ITO is deposited to form the common electrode 110. On the other hand, at the time of forming the common electrode, an Align Key for adhesion at the final step and a scribe key for cutting at a later stage may be formed, or a top plate may be Aligned by using Edge Align without a separate Align Key.

Next, as shown in FIG. 5C, a material such as copper, aluminum, or ITO is coated on the lower base substrate 230 on which the thin film transistor (TFT) 220 is formed to correspond to each of the sub pixels, A pixel electrode 210 is formed to correspond to each of the sub-pixels. Here, the pixel electrode 210 may be formed by further laminating nickel, gold, or the like on the above-described materials of copper, aluminum, and indium tin oxide (ITO). On the other hand, a gate line and a data line are formed on the lower base substrate, and the thin film transistor is formed in a region where the gate line and the data line cross each other. The data line is connected to the source electrode of the thin film transistor, the gate line is connected to the gate electrode of the thin film transistor, and the pixel electrode 210 is electrically connected to the drain electrode of the thin film transistor through the contact hole. On the other hand, since the electrophoretic dispersion liquid is directly coated on the lower substrate, it is preferable that the passivation layer 240 is an organic layer in terms of planarization. In addition, the passivation structure can be applied to various structures such as an organic insulator single or inorganic / organic, inorganic / organic / inorganic. In the present invention, a black layer 240 should be formed on a lower substrate for black implementation. In this case, the black layer may be formed in three types as described above. In particular, But may be formed in the form of a protective layer as shown in FIG. 5C using an organic insulating material having a black color instead of the material. Meanwhile, in the case where the barrier rib bottom electrode 316b is formed to correspond to the pixel electrode, the barrier rib bottom electrode may be formed together with the pixel electrode in FIG. 5C.

Next, as shown in FIG. 5D, the barrier ribs 314 are formed on the lower substrate on which the pixel electrodes are formed. The barrier ribs 314 may be formed by photolithography or mold printing and may be formed to have a height of 1 μm to 100 μm so that the electrophoretic dispersion 310 Define the pixel. That is, a barrier is formed to prevent color mixing of each color region of each sub-pixel, and various methods such as an imprinting method, a photolithography method, and a molding printing method may be applied as the barrier formation method. The barrier ribs are formed to have an appropriate thickness in accordance with the material characteristics. Meanwhile, it is possible to form the barrier ribs on the upper substrate, but it is advantageous to form the barrier ribs on the lower substrate rather than the upper substrate.

Next, as shown in FIG. 5E, the barrier rib electrodes 316 are formed on the inclined planes of the barrier ribs for the transverse electric field driving. 5E shows a state in which only the barrier face electrode 316a is formed as the barrier rib electrode 316. However, as described above, the barrier rib electrode may be formed using only the barrier lower end electrode 316b described in FIG. And may be formed to include both the barrier rib surface electrode 316a and the barrier rib bottom electrode 316b. The barrier rib electrode may be formed through various processes depending on the shape thereof.

That is, as described in, for example, Japanese Laid-Open Patent Publication No. 10-2001-0046458 (plasma display device having a barrier rib electrode and a manufacturing method thereof), the barrier rib electrode 316 may be formed After the barrier rib is formed, the barrier rib material may be directly formed on the barrier rib by a deposition process using a mask. After the barrier rib is formed, the barrier rib electrode material is filled in the sub pixel space, As shown in FIG. In this case, the line connected to each of the barrier rib electrodes may be formed on the lower substrate together with the pixel electrode during the process of forming the pixel electrode in FIG. 5C, and then connected to the barrier rib electrode through the process of FIG. 5E. In addition, each barrier rib electrode may be configured to be switched by another thin film transistor (not shown) formed by the gate line and the data line. That is, the method of forming the barrier rib electrode and the method of driving the barrier rib electrode may be configured in various ways.

Next, as shown in FIG. 5F, an electrophoretic dispersion liquid 310 including a plurality of white charged particles 312 charged with a positive (+) or negative (-) polarity is defined by the partition 314 And the electrophoretic dispersion liquid 310 is internalized in the lower substrate 200. [ The electrophoretic dispersion 310 may be formed by a variety of methods such as a die coating method, a casting method, a bar coating method, a slit coating method, a dispensing method, a squeezing method, Pixels may be internalized in the sub-pixel on the lower substrate 200 through a screen printing method, an inkjet printing method, and a photolithography method. In FIG. 5F, And the electrophoretic dispersion 310 is filled in the sub-pixel using the dispenser 400. FIG. On the other hand, various techniques disclosed in the above-described electrophoretic dispersion filling method can be applied. However, in the inkjet method, after aligning using a TFT Align Key, a method of dropping an electrophoretic dispersion on each sub- Can also be applied. Alternatively, an electrophoretic dispersion (Color Liquid) having white charged particles and a color may be injected separately according to the injection equipment or the process condition, or may be injected into a fluid form in which a mixture of white charged particles and color electrophoretic dispersion is mixed .

Finally, as shown in FIG. 5G, the upper substrate 100 and the lower substrate 200 are bonded together through the sealant with the electrophoretic layer 300 formed through the above-described process interposed therebetween. For this, the method of forming the top sealant 120 by coating the top sealant 120 on the upper substrate is used as described in the description of FIG. 5B. On the other hand, when the upper substrate and the lower substrate are bonded together, if the substrate is plastic, they may be bonded together by a laminating method. On the other hand, after the above-described process, a scribing process, a module process, and the like, which are not shown, can be performed, thereby finally completing the electrophoretic display device.

That is, in the electrophoretic display device according to the first embodiment of the present invention, the electrophoretic dispersion 310 filled in the sub-pixels through the above-described processes is formed on the barrier rib 314, the upper substrate 100, 200, and the white charged particles contained in the electrophoretic dispersion liquid are moved in accordance with the driving voltage of the pixel electrode or the barrier rib electrode, thereby realizing color, white or black.

FIG. 6 is a schematic view of an electrophoretic display device according to a second embodiment of the present invention, showing sub-pixels for displaying red, green, and blue.

6, an electrophoretic display device according to a second embodiment of the present invention includes an upper substrate 100 including a common electrode 110, a lower substrate 200 including a plurality of pixel electrodes 210, And a partition wall 314 on which a barrier rib electrode 316 is formed between the upper substrate 100 and the lower substrate 200. The barrier ribs 314 define a plurality of sub- And an electrophoretic layer 300 in which a defined sub-pixel is filled with an electrophoretic dispersion liquid 310, white charged particles 312 and black charged particles 318.

On the other hand, the electrophoretic display device according to the second embodiment of the present invention is similar in structure to the electrophoretic display device according to the first embodiment of the present invention shown in FIG. Therefore, description of the same components as the structure and function of the electrophoretic display device according to the first embodiment of the present invention will be omitted. Hereinafter, descriptions of the components of the electrophoretic display device according to the second embodiment of the present invention Only the components having the structure and function different from those of the electrophoretic display device according to the first embodiment will be described.

First, in the first embodiment of the present invention, only the white charged particles 312 charged with one and the same polarity are included in the electrophoretic dispersion 310 having color, but in the second embodiment of the present invention, In addition to the particles 312, black charged particles 318 having excellent light absorbing characteristics are further included, and white charged particles and black charged particles are charged to different polarities.

That is, if the white charged particles are charged with a negative polarity, the black charged particles are charged with a positive polarity. If the charged particles are charged with a positive polarity, the black charged particles are negatively charged. And is charged with polarity.

Here, the white charged particles 312 may be particles having excellent reflectivity such as TiO2 as described above, and the black charged particles 318 may have a black characteristic capable of absorbing light such as carbon black Particles may be used.

In the first embodiment of the present invention, a black layer is required to realize black. However, since black is implemented using black charged particles 318 in the second embodiment of the present invention, It is not necessary to provide a black layer as in the embodiment.

In other words, the electrophoretic display device according to the second embodiment of the present invention is different from the electrophoretic display device according to the first embodiment of the present invention except that it includes black charged particles in addition to white charged particles, And in structural terms.

Therefore, the electrophoretic display device according to the second embodiment of the present invention is not required to illustrate the black layer as shown in Fig. The electrophoretic display device according to the second embodiment of the present invention can be manufactured through the same process as shown in FIG. 5, except that the step of forming the black layer may be omitted, The electrophoretic dispersion 310 further contains black charged particles in addition to white charged particles.

On the other hand, the electrophoretic display device according to the second embodiment of the present invention includes black charged particles in addition to white charged particles. Therefore, in the method of representing color, white, and black, in the first embodiment of the present invention Which is different from the electrophoretic display device according to the present invention. Therefore, a method of representing color, white, and black in the electrophoretic display device according to the second embodiment of the present invention will be described in detail with reference to FIG.

7 is an exemplary view for explaining a method of displaying various colors using the electrophoretic display device according to the second embodiment of the present invention. Hereinafter, for convenience of explanation, the case where the white charged particles 312 are charged in the negative polarity and the black charged particles 318 are charged in the positive polarity will be described as an example. An embodiment is described.

First, when the electrophoretic display device according to the second embodiment of the present invention implements black, as shown in FIG. 7 (a), the pixel electrode 210 is provided with a positive +) ≪ / RTI > At this time, the white charged particles 312 charged with a negative polarity move in the direction of the pixel electrode and flocculate on the upper surface of the pixel electrode, and the black charged particles 318 charged with a positive And is moved toward the substrate to be concentrated on the surface of the upper substrate. Therefore, the light to be introduced into the sub-pixel through the upper substrate is absorbed by the black charged particles 318 disposed at the boundary between the sub-pixel and the upper substrate, and black is realized at this time.

Next, FIG. 7 (b) is for explaining a method of implementing white by using the electrophoretic display device according to the second embodiment of the present invention.

That is, when the electrophoretic display device according to the second embodiment of the present invention implements white, as shown in FIG. 7 (b), the pixel electrode 210 is provided with a negative -) polarity. At this time, the white charged particles charged with the negative (-) polarity move in a direction opposite to the pixel electrode, that is, in the direction of the common electrode formed on the upper substrate and are floated on the surface of the upper substrate, The black charged particles which are charged by the voltage application means flocculate on the surface of the pixel electrode. Therefore, the light that is to be introduced into the sub-pixel through the upper substrate is again reflected to the outside by the white charged particles 312 disposed at the boundary between the sub-pixel and the upper substrate, thereby realizing white.

7 (c) and 7 (d) illustrate a method of implementing a color using the electrophoretic display device according to the second embodiment of the present invention.

That is, when the electrophoretic display device according to the second embodiment of the present invention implements color, as a first method, as shown in FIG. 7 (c), a side wall electrode (+) Polarity having a polarity opposite to that of the black charged particles 318 is applied to the pixel electrode (side wall surface electrode) 316a, and a positive (+) polarity having a polarity opposite to that of the white charged particles 312 is applied to the pixel electrode Or as a second method, as shown in FIG. 7D, a side wall electrode (lower wall edge electrode) 316b formed horizontally with the pixel at the lower end of the side wall is provided with a negative -) polarity, and positive (+) polarity having a polarity opposite to that of white charged particles can be applied to the pixel electrode. At this time, the white charged particles charged with the negative polarity are floated on the pixel electrode, and the black charged particles charged with the positive polarity are charged to the side wall electrodes 316a or 316b formed on the right and left of the sub- So that it is concentrated on the side wall electrode. Accordingly, the light incident into the sub-pixel through the upper substrate is reflected toward the upper substrate by the white charged particles on the upper surface of the pixel electrode formed on the lower surface of the sub-pixel, And the color corresponding to the color liquid (red) of the electrophoretic dispersion liquid is realized because the electrophoretic dispersion liquid 310a inside the pixel is transmitted and emitted to the outside. On the other hand, in the second method using the sidewall bottom electrode 316b, some of the light that has flowed into the sub-pixel is not reflected by the white charged particles and the black charged particles 318 The color efficiency may be lowered because it can be absorbed by the sidewall bottom electrode. However, considering the problems in circuit implementation, the sidewall bottom electrode also needs to be considered.

As described above, the electrophoretic display device according to the second embodiment of the present invention differs from the electrophoretic display device according to the first embodiment of the present invention in that the method for realizing color, white and black is different from that of the electrophoretic display device according to the first embodiment of the present invention, The electrophoretic display device according to the second embodiment of the present invention is characterized in that two power sources having two different polarities are applied to the barrier rib electrode and the pixel electrode in order to express color. That is, as can be seen from FIG. 4, the electrophoretic display device according to the first embodiment of the present invention can express color, white and black by applying a power having any polarity, As shown in FIG. 7, the electrophoretic display device according to the second embodiment of the present invention is capable of expressing color only when two power sources having different polarities are applied.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: upper substrate 200: lower substrate
300: electrophoresis layer 310: electrophoresis dispersion
312: White charged particle 314: Partition wall
316: Bulkhead electrode 318: Black charged particle

Claims (14)

An upper substrate;
A lower substrate including a plurality of pixel electrodes;
Barrier ribs formed on the lower substrate and defining a plurality of sub-pixels;
A barrier rib formed on the barrier rib;
An electrophoretic dispersion contained in each of the plurality of sub-pixels defined by the partition and having a color; And
A charged particle contained in the electrophoretic dispersion liquid,
The charged particles are white charged particles having a property of reflecting light,
Wherein the barrier rib electrode and the pixel electrode are independently driven,
Each of the plurality of sub-pixels of the lower substrate includes a black layer for absorbing light introduced through the upper substrate through the sub-pixel to implement black,
When the charged particles are applied to the barrier ribs, the black layer absorbs the light that has flowed through the upper substrate through the sub-pixels, Wherein the electrophoretic display device has a black display. delete The method according to claim 1,
Wherein when the voltage of the opposite polarity to the polarity of the charged particles is applied to the pixel electrode, the charged particles are disposed on the pixel electrode, and light reflected by the charged particles causes the color of the electrophoretic dispersion inside the sub- And the electrophoretic display device. The method according to claim 1,
Wherein when a voltage having the same polarity as the polarity of the charged particles is applied to the pixel electrode, the charged particles are disposed at a boundary between the sub-pixel and the upper substrate, and light that is to be introduced into the sub- , And is reflected to the outside by the charged particles to realize white. delete delete delete delete delete delete Forming an upper substrate by forming a common electrode on a transparent upper base substrate;
Forming a plurality of sub-pixels each having a thin film transistor and a pixel electrode on a lower base substrate, forming a black layer on each of the plurality of sub-pixels to form a lower substrate;
Forming a barrier rib defining the sub-pixels on the lower substrate;
Forming a barrier rib electrode on the barrier rib;
An electrophoretic dispersion having color in each of the sub-pixels; and filling the charged particles; And
And adhering the upper substrate and the lower substrate with the barrier ribs interposed therebetween,
The charged particles are white charged particles having a polarity and reflecting light,
Wherein the barrier rib electrode and the pixel electrode are independently driven,
When the charged particles are applied to the barrier ribs, the black layer absorbs the light that has flowed through the upper substrate through the sub-pixels, Wherein the electrophoretic display device is a black electrophoretic display device. delete delete 12. The method of claim 11,
Wherein the black layer
Wherein the thin film transistor is formed on a front surface of the lower base substrate or on a protective layer for protecting the thin film transistor or on the front surface of the pixel electrode.

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